Apparatus and method for feeding a sinter mix onto a sinter strand



Jan- 27, 1970 L.. Pozf-:FSKY

APPARATUS AND METHOD FOR FEEDING A SINTER MIX ONTO A SINTER STRAND Filed March 6, 1968 INVENTOR Leo Poze fsk] United States Patent O 3,491,990 APPARATUS AND METHOD FOR FEEDING A SINTER MIX ONTO A SINTER STRAND Leo Pozefsky, Bethlehem, Pa., assignor to Bethlehem Steel Corporation, a corporation of Delaware Filed Mar. 6, 1968, Ser. No. 710,953 Int. Cl. F27d 3/06, 3/12 U.S. Cl. 263-28 3 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Particles of iron ore too fine to Ibe used as charge material in a blast furnace are mixed with particles of fuel and a flux and moisture is added to make a sinter mix. The sinter mix is fed to a sinter strand whereon a tired agglomerate suitable for charging into a blast furnace is formed. The sinter mix contains varying sizes of moist particulate material. It is common practice to charge the sinter mix to the sinter strand to make a bed having uniform distribution of all the particles and moisture. However, it is known that more fuel is needed in the top of the bed than in the lbottom to obtain proper ignition and more importantly to improve the heat balance in the sintering process. It is also known that too much moisture in the bottom of the bed may cause bed collapse. Adding more fuel to the mix to improve quality in the top of the sinter bed results in excess fuel in the lower portions of the sinter bed causing slagging thereby decreasing perme-ability of the bed and reducing sintering rates. Increasing the start ignition, laying the sinter bed in double layers and the use of preheated air immediately following ignition of the mix can improve the strength of the upper layers of the sinter bed but at the expense of a reduced sintering rate. The moisture required in the sinter mix to produce the optimum sinter bed permeability is dependent on the type of materials, their proportions -and their size. One proposed method to obtain sizesegregation in a sinter bed is to feed the sinter mix against a series of bales to obtain size distribution in the bed. However, such apparatus is complicated, expensive and of doubtful efficiency.

It is therefore the object of this invention to provide apparatus and a method for feeding a sinter mix to a sinter strand which is economically feasible and which will assure a sinter 2bed having the desired fuel and moisture and size distribution.

SUMMARY OF THE INVENTION Broadly the apparatus includes a feed hopper having an open top and a discharge aperture at the bottom to feed the sinter mix in a ribbon-like layer to a rotatable drum. The drum rotates countercurrently to the direction of movement of the sinter strand to thereby deposit the sinter mix on the sinter strand as the strand approaches the feed hopper.

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BRIEF DESCRIPTION OF THE DRAWING The drawing is an elevation of the apparatus of the invention. f

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, the sinter mix which consists essentially of various size particles of iron ore, fuel land ux to which a quantity of water has been added, is charged into a feed hopper shown generally at 10. The feed hopper 10 is a box having an upper portion 11 which is generally rectangular in cross section and a lower portion 11a having two walls 13 and 13a which converge to form a discharge aperture 14 and two end walls 15 and 15a. Interposed between the discharge aperture 14 and the sinter strand 12 is a rotatable drum 16 extending the width of the sinter strand 12. The drum has an outer cylindrical surface 17 and closed ends 18 which extend beyond the outer surface 17 to prevent spillage of the sinter mix. The drum may be rotated at varying speeds by conventional means, for example, a variable speed electrical motor or motor-generator set (not shown). Adjustable plates 13b and 13u.` are slidably attached to the walls 13 and 13a respectively to control the amount of sinter mix which may be fed from the hopper 10 through aperture 14 to the sinter strand 12 by the drum 16. The sinter strand 12 is made of a series of pallets 19 mounted on rollers 20 which engage a track 21. A levelling plate 22 is provided to level off the sinter bed 23 on the sintering strand 12 as it passes beneath the drum 16.

The sinter mix is discharged from the hopper 10 through the discharge aperture 14 onto the surface 17 of the drum 16. The drum 16 is rotated in a direction such that the upper half thereof is rotating in a direction countercurrent to the direction of movement of the sinter strand 12.

As the sinter mix passes from the discharge aperture of the hopper yand is deposited on the rotating drum, a velocity is imparted to the particles in the sinter mix by the rotation of the drum. The coarser particles will travel a greater distance than the liner particles and a rst layer of coarse particles will be formed on the pallets of the sinter strand at a distance upstream from the drum. As the strand moves toward the drum, the finer particles will be deposited atop the first layer of coarser particles downstream from the point at which the coarser particles had been deposited. Since the ore particles are usually larger than the fuel particles, a sinter =bed will be formed having a major portion of the coarse ore particles in the lowermost layer `and a major portion of the fuel particles in the uppermost layers. Of course there will be a gradation of coarse particles to fine particles from the bottom to the top of the sinter bed. Because the tine particles in the sinter mix, particularly the fuel particles, contain more moisture than the coarser particles there will also be a segregation of moisture content in the uppermost layers of the sinter bed. The sinter bed thus formed has the fuel, moisture and coarser particles segregated in desired locations. It must be understood that the speed of the drum can be varied to o'btain varying degrees of size segregation in the sinter bed. The greater the speed of rotation the greater the portion of coarser particles in the lowermost layers of the sinter bed and the greater the portion of fines, fuel and moisture in the uppermost layers of the sinter bed.

il claim:

1. A method for controlling the material segregation and size distribution of a particulate moist sinter mix containing fuel, iron ore and llux onto the pallets of a sintering strand, comprising:

(a) feeding the particulate moist sinter mix into a feed hopper,

(b) feeding the particulate moist sinter mix from the hopper onto the surface of a rotatable cylindrical drum,

(c) rotating the cylindrical drum in a direction countercurrent to the direction of movement of the pallets of the sintering strand at a speed sufficient to deposit the coarser particles of the mix onto the pallets at a point upstream from the point at which the liner particles of the mix are deposited.

2. The method of claim 1 in which a sinter bed is formed having a major portion of the coarser particles therein deposited in the lowermost layer thereof and a major portion of the ner particles deposited in the uppermost layer thereof, and intermediate layers therebetween containing a portion of coarse particles and a portion of fine particles.

3. Sintering apparatus for particulate material of varying sizes comprising:

(a) a plurality of pallets provided with grates on which the material is to be sintered;

(b) means for moving the pallets along a desired path;

(c) a discharge chute for the material, located above the pallets; Y

(d) a drum disposed between the chute and said pallets with its axis horizontal and at right angles to the direction of movement of the pallets, for receiving the material discharged from the chute;

(e) means for rotating the drum in a direction such that the direction of movement of the upper half of the drum is opposite to that of the pallets and at a speed such that the larger particles of the material are fed onto the pallets at a point farther upstream than the smaller particles of the material.

References Cited UNITED STATES PATENTS 1,906,755 5/1933 Karrick 266-21 2,726,079 12/1955 Sheets 266*21 2,933,306 4/1960 Davis et al. 266--21 3,262,770 7/1966 Tsujihata et al. 266--21 JOHN I. CAMBY, Primary Examiner U.S. Cl. X.R. 266-21 

